1. Field of the Invention
The present invention relates to a method of producing a polymer dispersed liquid crystal device with a cooling plate and a polymer dispersed liquid crystal device using the same.
2. Discussion of Related Art
Existing eyeglasses used by people with weak vision are of a fixed strength, and thus it is necessary to replace the eyeglasses as vision worsens. Especially, when farsightedness occurs as people age, people who were already myopic have difficulty seeing text both near and far. Out of existing eyeglasses, sunglasses are widely used by people with normal vision to block direct sunlight and UV rays, especially overseas. In recent years, in order to find solutions to the problems of the existing eyeglasses, research on smart electronic eyeglasses has been underway. The principle is using an optical shutter function for blocking or transmitting light which is a fundamental role of the liquid crystal. The optical shutter employing such liquid crystal is referred to as a crystal device, or simply a device, in order to differentiate it from the existing eyeglasses. The crystal device can be electronically operated based on the external light intensity. When the external light intensity is high, that is, light is strong, the liquid crystal shutter is largely open, whereas when light is weak, the liquid crystal shutter opens little so as to control the amount of light. By combining these features with an electronic circuit serving as a switch in addition to a sensor for measuring the external light intensity, it is possible to configure electronic eyeglasses employing a so-called autoshading function of a crystal device which performs more active functions than the sunglasses. In addition, a focal length of the crystal device can be adjusted by controlling the voltage applied to the electrodes which are divided into multiple levels such that electrodes are effectively arranged in the vicinity of high-refractive-index liquid crystal or the crystal device is formed in a three-dimensional manner. In this case, by combining a distance measurement sensor with an electronic circuit having an electrode driving control function, it is possible to manufacture electronic eyeglasses having a strength function which can cope with myopia or hypermetropia. Further, the smart electronic eyeglasses in which the above-described autoshading function and the degree function are combined and a variety of software is installed are under development.
Such a crystal device uses a nematic liquid crystal in the manufacturing of a TFT-LCD. Due to the limitation of the material itself, the reaction rate of the nematic liquid crystal is relatively slow, and a manufacturing process thereof is complex, requiring many manufacturing facilities. Further, additional films such as a polarizing plate are necessary. In particular, in terms of the basic principle of the nematic liquid crystal, polarizing plates are attached to the front and rear surfaces of the nematic liquid crystal device one by one, and thus the cost increases and light transmittance is reduced by 35% or more. Furthermore, a very complex process including an alignment process using polyimide and a liquid crystal injection process degrades a yield of the nematic liquid crystal and the productivity.
Recently, in order to overcome the shortcomings of such a nematic liquid crystal device, new liquid crystal materials and crystal devices have been proposed.
In terms of the basic principle of the nematic liquid crystal, with simple manufacturing processes and manufacturing facilities, the polymer dispersed liquid crystal does not require the polarizing plate and the polyimide alignment for an array of liquid crystal. As a result, light transmittance reaches 100% in theory and it is possible to overcome most problems of the nematic liquid crystal described above.
However, because a material made of a polymer is employed, the polymer dispersed liquid crystal device has a problem in that a driving voltage is higher than the nematic liquid crystal. When the driving voltage is high, an electrical efficiency for driving the polymer dispersed liquid crystal device decreases and the battery consumption increases. Further, it is very dangerous since the user wears the electrical eyeglasses in front of her or his eyes. When the driving voltage is 30 V or more, the manufacturing cost of a driving circuit increases greatly. Accordingly, it is necessary to improve the characteristics of the driving voltage, which is one of the biggest shortcomings of the polymer dispersed liquid crystal device.